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arXiv · 1205.4125

Study of the Two-Gap Superconductivity in GdO(F)FeAs by ScS-Andreev Spectroscopy

T. E. Shanygina·Ya. G. Ponomarev·S. A. Kuzmichev·M. G. Mikheev·S. N. Tchesnokov·O. E. Omel'yanovsky·A. V. Sadakov·Yu. F. Eltsev·V. M. Pudalov·A. S. Usol'tsev·E. P. Khlybov·L. F. Kulikova
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Abstract

Current-voltage characteristics and dynamic conductance of the superconductor - constriction - superconductor junctions in GdO(F)FeAs polycrystalline samples with critical temperatures Tc^local = 46 - 53 K were investigated. Two superconducting gaps, the large Delta_L = 10.5 +- 2 meV, and the small one Delta_S = 2.3 +- 0.4 meV were clearly observed at T = 4.2 K. The 2Delta_L/kTc^local = 5.5 +- 1 ratio gives support to the strong coupling mechanism which is responsible for the high Tc value. Temperature dependence of the large gap Delta_L(T) indicates the presence of intrinsic proximity effect (in k-space) between two superconducting condensates.

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T. E. Shanygina, Ya. G. Ponomarev, S. A. Kuzmichev, M. G. Mikheev, S. N. Tchesnokov, O. E. Omel'yanovsky, A. V. Sadakov, Yu. F. Eltsev, V. M. Pudalov, A. S. Usol'tsev, E. P. Khlybov, L. F. Kulikova. 2012-05-18. Study of the Two-Gap Superconductivity in GdO(F)FeAs by ScS-Andreev Spectroscopy. https://doi.org/10.1088/1742-6596%2F391%2F1%2F012138

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